JP5630614B2 - Gas tank manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a gas tank that is filled with a gas such as hydrogen at high pressure.

  A high-pressure gas tank filled with a gas such as hydrogen has a tank body in which a liner formed from a resin or the like is covered with a fiber reinforced resin layer made of carbon fiber or the like.

  As a technique for curing such a fiber reinforced resin layer, a molding material layer having inner and outer layers made of fiber reinforced resin is formed on the inner and outer surfaces of an intermediate layer made of resin mortar around a core mold made of a steel belt, It is known to heat and cure a molding material layer (see, for example, Patent Document 1). In this technique, it is shown that a conductive material is put into a resin mortar to form an intermediate layer, and a core mold composed of the intermediate layer and the steel belt is induction-heated by high-frequency induction means to cure the molding material layer.

  Further, there is known a vulcanization apparatus that performs heating and holding by electromagnetic induction on a laminate obtained by alternately laminating unvulcanized rubber and metal plates and a mold that holds the laminate (for example, Patent Document 2). reference). This apparatus has an induction coil for applying a magnetic field to a metal plate and a mold, a power supply means for supplying an alternating current to the induction coil, and a frequency adjustment means for adjusting the AC power supply. The frequency adjustment means is a power supply means. Low frequency conversion means for converting the AC power supply to low frequency, high frequency conversion means for converting the AC power supply of the power supply means to high frequency, and waveform addition means for superimposing the high frequency on the low frequency.

Japanese Patent Laid-Open No. 10-337784 Japanese Patent Laid-Open No. 11-240019

  By the way, even if the fiber reinforced resin layer of the tank is heated from the outer layer side by the induction heating technique as in Patent Document 1, the heating current hardly penetrates into the inner layer part of the fiber reinforced resin layer. A difference in speed occurs, resulting in variations in the cured state. In addition, since the heating current of induction heating has different penetration levels depending on the heating frequency, the heating efficiency decreases as the penetration frequency decreases.

  Moreover, when heating is performed only by external heating, it takes time to raise the temperature to the inner layer portion of the fiber reinforced resin layer, and it takes a long time to cure the whole. In addition, only the outer layer portion may be cured and the inner layer portion may be insufficiently cured, or performance degradation or quality variation may occur. Furthermore, if the outer layer portion is cured first, residual bubbles in the layer may not be smoothly removed when the resin is cured, and voids or the like may occur in the fiber reinforced resin layer, resulting in poor appearance and reduced performance.

  In the technique of Patent Document 2, the temperature of the entire laminate can be raised to a constant temperature range (vulcanization temperature range) at a uniform temperature by matching the temperature increase rates of the metal plate and the mold. It was necessary to perform complicated processing such as superimposing a high frequency on the surface.

  The present invention has been made in view of the above circumstances, and by heating the fiber reinforced resin layer uniformly, the fiber reinforced resin layer is cured uniformly in a short time, the appearance is good, and the quality Provides a stable gas tank manufacturing method.

In order to achieve the above object, the gas tank manufacturing method of the present invention comprises a gas tank having a fiber reinforced resin layer in which reinforcing fibers made of an inductive material impregnated with a thermosetting resin are wound and laminated on the outer peripheral side of a liner. A manufacturing method of
By winding a conductive wire together with the reinforcing fiber, an inner coil made of the conductive wire is provided on the inner layer portion of the fiber reinforced resin layer, and an outer coil is wound around the outer periphery,
The thermosetting resin is heated and cured by causing currents of different frequencies to flow through the internal coil and the external coil to heat the reinforcing fibers.

  According to such a manufacturing method, an internal coil is provided in the inner layer portion of the fiber reinforced resin layer, and an external coil is wound around the outer periphery, and currents of different frequencies are supplied to the internal coil and the external coil to generate heat. . For example, the frequency of the current flowing through the external coil is set lower than the frequency of the current flowing through the internal coil. As a result, the fiber reinforced resin layer is heated uniformly and rapidly from the inner layer portion to the outer layer portion without complicated treatment, and the fiber reinforced resin layer is cured uniformly in a short time. Further, it is possible to easily and quickly manufacture a gas tank in which the generation of voids is suppressed, the appearance is good, and the quality is stable.

  In the above manufacturing method, the frequency of the current flowing through the external coil may be lower than the frequency of the current flowing through the internal coil.

  In the manufacturing method, a current may be passed through the internal coil before a current is passed through the external coil.

  According to the present invention, there is provided a method for producing a gas tank in which a fiber reinforced resin layer is uniformly heated in a short time and cured in a short time and uniformly to have a good appearance and a stable quality. Can be provided.

It is sectional drawing which shows the whole structure of a gas tank. It is an enlarged view of the A section in FIG. It is a perspective view which shows the winding process of a reinforced fiber. It is a perspective view which shows the winding process of a reinforced fiber. It is a perspective view which shows the winding process of a reinforced fiber. It is a perspective view which shows the heat-hardening process of a fiber reinforced resin layer.

  Hereinafter, a gas tank manufacturing method according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows a gas tank 11 for filling and storing a high-pressure gas (for example, hydrogen gas) inside. The gas tank 11 has a tank body 14 having a configuration in which the outer peripheral side of a liner 12 made of synthetic resin or aluminum is covered with a fiber reinforced resin layer 13 made of an inductive material such as carbon fiber. The liner 12 constituting the tank main body 14 is formed by abutting a pair of liner divided bodies 12a with each other and joining them together by laser welding or the like.

  At both ends of the tank main body 14, a base member (base) 16 is attached to a mouth portion 15 formed in the liner 12, and the side having the base member 16 to which the valve can be attached is a valve side, and the opposite side is It is the end side.

  The base member 16 is formed with a flange portion 22 at an intermediate portion on the outer periphery, and the base member 16 is attached to the liner 12 by being press-fitted into the mouth portion 15 until the flange portion 22 contacts the liner 12. It is done.

  As shown in FIG. 2, the fiber reinforced resin layer 13 is composed of a fiber layer 13a such as a helical layer formed by helical winding and a hoop layer formed by hoop winding. An internal coil 31 made of a conductive wire such as a copper wire or copper foil is spirally wound around the fiber reinforced resin layer 13 in the axial direction of the tank body 14. The internal coil 31 is disposed in the inner layer portion in the fiber reinforced resin layer 13. The inner coil 31 may be in contact with the liner 12 when the liner 12 is made of a nonconductive material such as a synthetic resin or aluminum.

  Both ends of the conductive wire constituting the internal coil 31 are wound around the base members 16 provided at both ends of the tank body 14 and are electrically connected to these base members 16.

Next, the case where the gas tank 11 is manufactured will be described.
As shown in FIG. 3, the reinforcing fiber 35 fed out from the bobbin is wound around the outer periphery of the liner 12 to which the cap member 16 is attached by a filament winding method using a fiber winding device while applying a predetermined tension. The reinforcing fiber 35 is made of a prepreg, and the prepreg is previously impregnated with a semi-cured thermosetting resin such as an epoxy resin, a modified epoxy resin, or an unsaturated polyester resin. The reinforcing fiber 35 may be a single fiber that is not a prepreg.

  The fiber winding device includes an air 41 that is a guide that reciprocates along the axis of the liner 12. And the winding position of the reinforced fiber 35 with respect to the liner 12 rotated centering on an axial center is moved by this iron 41. Thereby, the reinforcing fiber 35 is alternately wound around the outer periphery of the liner 12 by helical winding and hoop winding, thereby forming the fiber layer 13a.

  At the time of winding the reinforcing fiber 35, as shown in FIG. 4, the inner coil 31 made of a conductive wire such as a copper wire or a copper foil is spirally wound around the liner 12 by hoop winding. At this time, the internal coil 31 winds the winding start end around one base member 16 of the liner 12 and winds the winding end end around the other base member 16 of the liner 12. When the internal coil 31 is wound around the inner layer portion, the reinforcing fiber 35 is wound again as shown in FIG.

  Thereafter, helical winding and hoop winding of the reinforcing fiber 35 are repeatedly performed until the required layer thickness is obtained, thereby forming the fiber reinforced resin layer 13 in which the inner coil 31 is wound and embedded in the inner layer portion. When the liner 12 is made of a nonconductive material such as a synthetic resin or aluminum, the internal coil 31 may be wound directly around the liner 12.

  As described above, when the fiber reinforced resin layer 13 having the inner coil 31 in the inner layer portion is formed on the outer periphery of the liner 12 to form the gas tank 11, as shown in FIG. The external coil 32 made of a low frequency current coil is wound around the gas tank 11 and disposed.

  In this state, the electrodes of the induction heating device (not shown) are connected to both ends of the cap member 16 and both ends of the external coil 32 to which the internal coil 31 is connected. A heating current is passed through the internal coil 31 and the external coil 32 by the induction heating device.

  Then, the heating current flows through the internal coil 31 and the external coil 32 between the cap members 16. Thereby, in the fiber reinforced resin layer 13, the reinforcing fibers 35 on the inner layer portion side generate heat by the internal coil 31, and the reinforcing fibers 35 on the outer layer portion side generate heat by the external coil 32. Thereby, in the fiber reinforced resin layer 13, a thermosetting resin is heated and induction heating hardening is started.

  At this time, currents having different frequencies are passed through the internal coil 31 and the external coil 32. Specifically, the frequency of the current flowing through the external coil 32 is set lower than the frequency of the current flowing through the internal coil 31. For example, the frequency of the current flowing through the external coil 32 is 1 kHz or less, and the frequency of the current flowing through the internal coil 31 is 2 to 3 kHz.

  Here, the fiber reinforced resin layer 13 of the gas tank 11 is heated only from the outside, and even if the temperature of the outer layer portion is increased, the temperature increase of the inner layer portion is insufficient, and the curing of the thermosetting resin varies.

  In the present embodiment, the internal coil 31 is provided in the inner layer portion of the fiber reinforced resin layer 13, and a low-frequency current having a deep current penetration depth flows through the external coil 32, while the current permeability depth is relatively low in the internal coil 31. A high-frequency current that is shallow but has a high heat generation effect is passed. Thereby, the fiber reinforced resin layer 13 is uniformly and rapidly heated from the inner layer portion to the outer layer portion to increase the temperature, and the thermosetting resin is cured without variation throughout the fiber reinforced resin layer 13.

  When the thermosetting resin of the fiber reinforced resin layer 13 is completely cured and the gas tank 11 is completed, the gas tank 11 is taken out from the induction heating and curing furnace 42 and the external coil 32 is removed.

  Thus, according to the manufacturing method of the gas tank of the said embodiment, while providing the internal coil 31 in the inner-layer part of the fiber reinforced resin layer 13, winding the external coil 32 around the outer periphery, the internal coil 31 and the external coil 32 are arranged. In addition, the reinforcing fibers 35 are heated by flowing currents of different frequencies. Specifically, the frequency of the current flowing through the external coil 32 is set lower than the frequency of the current flowing through the internal coil 31.

  Accordingly, the fiber reinforced resin layer 13 is heated uniformly and rapidly from the inner layer portion to the outer layer portion without performing complicated treatment, and the fiber reinforced resin layer 13 is cured uniformly in a short time. Thus, generation of voids is suppressed, the appearance is good, and the gas tank 11 with stable quality can be manufactured easily and in a short time.

  Further, if the current is controlled to flow through the internal coil 31 before the current flows through the external coil 32, the fiber reinforced resin layer 13 is heated in a more balanced manner while suppressing the generation of voids. It can be cured uniformly.

  Further, since the internal coil 31 is connected to the base members 16 at both ends of the liner 12, the inner layer portion of the fiber reinforced resin layer 13 can be easily induction-heated by passing a heating current between the base members 16. it can.

  Further, the diameter, winding pitch, and the like of the internal coil 31 and the external coil 32 wound around the liner 12 can be easily adjusted according to the curing characteristics of the resin of the fiber reinforced resin layer 13.

  In the heat curing step of the fiber reinforced resin layer 13, the frequency and output of the heating current that flows to the internal coil 31 and the external coil 32 may be feedback controlled according to the cured state of the fiber reinforced resin layer 13, as described above. If the cured state of the fiber reinforced resin layer 13 is managed by feedback control, the fiber reinforced resin layer 13 can be further uniformly cured to improve the quality.

  DESCRIPTION OF SYMBOLS 11 ... Gas tank, 12 ... Liner, 13 ... Fiber reinforced resin layer, 31 ... Internal coil, 32 ... External coil, 35 ... Reinforcing fiber

Claims (2)

A method for producing a gas tank having a fiber reinforced resin layer in which reinforcing fibers made of an inductive material impregnated with a thermosetting resin are impregnated around an outer periphery of a liner,
By winding a conductive wire together with the reinforcing fiber, an inner coil made of the conductive wire is provided on the inner layer portion of the fiber reinforced resin layer, and an outer coil is wound around the outer periphery,
By causing currents of different frequencies to flow through the internal coil and the external coil to heat the reinforcing fibers, the thermosetting resin is heat-cured ,
A method for manufacturing a gas tank in which a current is passed through the internal coil before a current is passed through the external coil .   The method for manufacturing a gas tank according to claim 1, wherein a frequency of a current flowing through the external coil is set lower than a frequency of a current flowing through the internal coil.